Effect of TiN on microstructure and properties of Co-based alloy coating by laser cladding

Co-based alloy and TiN/Co-based alloy composite coatings were obtained on low carbon steel surface by 5 kW CO2 laser. Microstructure, phases, micro-hardness, and sliding wear resistance of the coatings were studied. The results show that the Co-based alloy coating consists of γ-Co, ε-Co, Cr23C6, and the TiN/Co-based alloy composite coating consists of γ-Co, ε-Co, Cr23C6, TiN, TiC. The Co-based alloy coating is made up of flourishing γ-Co dendrite and eutectic structures. Equiaxed solid solution and fine eutectic structure are observed in the TiN/Co-based alloy composite coating. The influence of TiN particles on microstructure of the Co-based alloy coating is prominent that TiN refines the microstructure by changing it from dendrited to equiaxed grain.